1. Field of the Invention
The invention relates to a pressure centrifuge and more particularly to a multiple drum element decanting centrifuge.
2. Description of the Related Technology
A pressure decanter is shown in a Krauss-Maffei prospectus illustrating the type KVZ/KVZ S decanting centrifuge, 1st edition, Order No. 22 03 d, page 4, where a drum and a screw rotate within a pressurized housing at different rates. Position 2 illustrated in the Figure on page 9 of the aforecited prospectus showns an inner seal between the screw and the drum for sealing the internal space of the housing and the processing chamber, which is under the operating pressure, from the atmosphere. The dry-running rotating mechanical seals are used for sealing the process chamber which is surrounded by the pressure housing, only up to definite limited pressure and temperature conditions.
The sealing action may be improved by lubricating the rotating mechanical seal with lubricating oil used for the bearings. Such lubrication is, however, not feasible when products are processed which must not come into contact with oil leaking from the rotating seal under any conditions.